Regulating device for clockwork-operated mechanical fuses for artillery projectiles



June 24, 1930.

REGULATING DEVICE FOR, CLOCKWORK OPERATED IECHANICAL FUSES FOR AR'I'ILLERY PROJECTILES Filed May 26, 1927 v 4 Sheets-Sheet 1 A VARAUD 1,767,493

J ,v 1930- A. VARAUD 1,767,493

REGULATING DEVICE FOR CLOCKWORK OPERATED MECHANICAL FUSES FOR ARTILLERY PROJECTILES Filed May 26, 1927 4 Sheets-Sheet 2- Q I A "x, I

June 24, 1930.. v VARAUD 1,757,493v

REGULATING DEVICE F0 LOCKWQRK OPERATED MECHANICAL FUSES FOR TILL PROJEGTILES v Fi1 May 1921 4 Sheets-Bheef 3 June 24,1930. RAUD 1,767,493

vREGULA IING13E E F0 L KWORK OPERATED MECHANICAL FU 0 ARTILL PROJEGTILES v ed May 1927 4 Sheetsfihgej; 4

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Application filed'May 26, 1927, Serial No.

Heretofore it has been proposed to employ a regulating device for clock work operated mechanical fuses for artillery projectiles comprising a cylindrical torsion spring in the form of a spiral'and arranged in such a manner that the axis of oscillation of said spiral coincides with the axis of the fuse and hence with the axis of rotation of the jectile during its trajectory; However, such against disturbing influences of centrifugal force and against other physical influences produced by the rapid rotation of the projectile during its trajectory. However, such devices as hitherto known have proved unsatisfactory and therefore have beenfabandoned.

The unsatisfactory results of such devices are due to different causes, particularly to the following:

First of all and contrary to the assertions advanced, a spiral arranged in the axis of rotation of the projectile is forcibly subjected to the action of centrifugalforce, particularly because, of the great rotary speed of modern artillery projectiles. In fact the centrifugal power tends to increase the extension of the spiralwhilst it opposesits contraction, a feature which accounts for an enormous retardation in the running of clock v work movement, even in cases where cor.-

responding tests had been made. under apparently very say, even if a deadbeat escapement without back-lash of the type tobe described later on has been employed; I

It will also be understood that with such an arrangement of the spiral the enormous retardation in clock work movements, which has been-stated to be as high as 100%, is

due to the irregular oscillations of the balanceproduced by centrifugal force, particularly in the case of alight mutation of the projectile.- I I I.

, Another reason which may account for the failure of such knowndev'ices resides in the fact that the use of ordinary escapements makes it impossible to obtain sufficiently free oscillations of the balance and hence no os -cillati'ons of great amplitude.

"Since in clock work operated fuses it is,

' devices,

good conditions, that is to 194,271, and in Switzerland May 28, 1926.

necessary to make use of a very strong power 7 spring in order to overcome the physical effects due to the rotation and t0 thenutation of the projectile, the power which the recolling escapement wheel has to overcome during its stop intervals becomes too great for permitting it to impart to the balance oscillations of a great amplitude and to obtain the isochronism of these oscillations by means of a regulating spiral.

In the drawing Figure 1 isa partial longitudinal section illustrating one embodiment of my present invention. v

Fig. 2 is a section on line II- -II, Fig.1, Fig. 3 is a plan of the parts shown in Fig. 1 with certain elements removed for clear-- nessof illustration, i

Figs. 4.- and 5 are plans of the split ring i Fig, 6 is a central longitudinal section illustrating the braking device, I

Figs. 7 and 8 are respectively a partial plan and longitudinal section illustrating another form of dead beat escapement mechanism, i 7

Figs; 9 and 10 are diagrammatic plans illustrating a third form of dead heat escapement mechanism, and 7 1 Figs. 11, 12 and 13 are diagrammatic plans illustrating still another form of dead beat escapement mechanism. v

:From the drawing it is seen that the drivingpower derived from the power spring 1 is transmitted to the regulating device by means'of a barrel shaft 2 to which is fixed e a crown wheel 3 fitted with internal teeth. This'crown wheel is part of a gear train, the other members of which are the gears 41-, 5, 6, 7, 8. The last gear of this train is an angle pinion 8 keyed on one end of a 1 j the spiral spring 19 of the balance.

pulses are imparted alternately first in one direction and then in the other direction on both sides of the spindle 13 by the pressure exercised by the inclined faces of the teeth the two Jart wheel actin on the sec-' tor, and the stop is effectedwithout any back-lash of the escapement wheel11each time the point of one of the teeth of this wheel rests upon the top surface of the pallet 12. p

The axis of the spindle 13 lies in the axis :v 2 of the fuse and carries the balance 14 The balance preferably consists of two blades, one being a prolongation of the other. Each one of these blades is made of a thin and flexible strip of metal and carries on its free end a small weight.

The'portion of the housing of the clocx work movement containing the regulator preferably consists of two cross plates 15 which are spaced from one another by means of three pillars 16. This portion of the housing is fitted with slight friction, so that it may rotate freely around its own axis, in circular grooves 17 provided therefor in the casing 18. This casing 18 is made of two semi-cylindrical parts. The upper plate 15 is made in the form of a drum in which is lodged the balance 14a and The axis of the spring 19 is coincident with the axis mz which is the axis of the fuse and that of the projectile. At one end the spring 19 is fixed to a collet 20'mounted on a half-fiat shoulder 21 (Fig. 1) on the spindle 13. At its other end the spring 19 is connected to a split ring 22 whose angular position may be adjusted within a small cylindrical shoulder provided in the center of a disk 23 which is fixed by means of four screws 24; in a circular notch in the cover 25 of the upper plate 15. The upper end of the spindle is journaled in this disk 23.-

In order to maintain the ring 22 in an ad justed position thepoints of the screws of an end pivot plate 26 screwed on the disk 23 are employed. The said ring 22 has a cylindrical projection on which a split ring 27 is frictionally mounted. The .ring 27 functions as a regulator in the following manner: The regulator ring 27 is provided on its inner surface with a small stud 28 through which the last or upper convolution of the spring 19 passes freely so that whenever the regulator ring 27 is angularly displaced with regard to the ring 22, the working length of the spring 19 is adjusted. In order to make this adjustment the regulator rin 27 is toothed on its pe 'riphery and a circular opening 29 (Fig. 3) is provided in the disk 23 in order that a toothed driving key (not shown in the drawing) .may be introduced. By this or equivalent means the regulator ring 27. may

be adjusted. The ring 22 and the regulator ring 27 are fixed underneath the disk 23 in their axial direction by means of a washer 30 made of two parts and placed between the disk 23 and the cover 25. The convolutions of the spring 19 are preferably of square section and are sufiiciently close together to allow the spring to momentarily rest upon the balance 14: at the moment of firing during the inertia effect. 31 (Fig. 2) indicates an inertia pin of known type for maintaining the balance in an initial position until the moment of firing the projectile.

The operation of this embodiment of the invention is as follows:

The fuse is mounted in the nose of the projectile in such a manner that its axis osy coincides with the axis of the latter and the balance 1% is locked until the moment of firing by means of the pin 31 which is a utomatically withdrawn by inertia at the moment the projectile is fired.

The relative position of the balance and the escapement wheel is adjusted in the course of manufacture by means of the split ring 22 in such a manner that one of the teeth of the escapement wheel is normally in a. position to cause it when released to give the first impulse to the balance, and the spiral 19 is also adjusted by means of the regulator ring 27. As soon as the balance 1% is liberated the escapement wheel thus gives an impulse to the balance and thereafter is at rest without recoiling on itself during the whole duration of the oscillation of said balance. At the end of this oscil lation the tooth which determined the rest imparts in its turn a second impulse to the balance in the opposite direction and the adjacent tooth then arrives at its rest position, and so on.

If in the fuses provided with the type of regulator as described it is observed that the clock work goes too slowly and this appears to be due to the fact that the nutation and the precession of the proj ectile hamper the regular operation of the balance, it is possible to eliminate or at least to considerably reduce these irregularities by submitting to the centrifugal force a movable member which is in such a mechanical connection with the spindle 13'of the balance 14 that it exercises a slight braking action during the whole duration of the trajectory of the projectile, the braking action being proportional to the rotary speed of the projectile.

A device of this nature is illustrated in Fig. 6 in which the spindle 13 carries a pinion 32 which engages with a wheel 33 keyed on the small spindle 34; journaled in bearings provided therefor. The gears 32 and 33 might be replaced by bevel-gears. In such a structure the small spindle 34!: would be arranged radially instead of being paralmight be made use of, in which the escape mentwheel does not recoil on itself during,

the rest period.

For instance the dead heat escapement called duplex might be employed in which the escapeinent wheel is provided with two sets of teeth of difi'erent diameter, as shown in Figs. 7 and 8. In this structure the teeth of larger diameter serve for the non-recoil-' ing rests and the teeth of smaller diameter for imparting the impulses.

A dead beat escapment of the detent type might also be used in which the rests are effectedwithout a back-lash or recoil of the escapement wheelagainst a member termed detent entirely independently from the balance spindle, as shown in Figs. 9 and 10.

Finally a dead beat escapement called detached anchor escapement might be employed in which the lockings take place- 7 also without any back-lash of the escapenient wheelagainst the lever of an anchor rigidly connected to an oscillating member called the fork transmitting the impulses to the balance, as shown in Figs. 11, 12 and 13.

I claim as my invention:

1. In a clock work operated mechanical fuse for artillery projectiles, a regulating device including a balance spindle, a balance carried thereby, a balance spring, a dead beat escapeineiit permitting no backlash in the balance, means for driving the escapement, and a rotary body mounted eccentrically to the axis of the balance spindle and associated therewith whereby the action of centrifugal force on the said rotary body produces a braking effect on the spindle and balance in proportion to the rotary speed of the projectile.

2. In a clock work operated mechanical. fuse for artillery projectiles, a regulating device including a balance spindle, a bal ance carried thereby, a balance spring, a dead beat escapement permitting no backlash inthe balance, means for driving the.

escapement, a gear mounted eccentrically to the axis of the fuse and that of the balance spindle, and a gear carried by the balance spindle and meshing with the aforesaid eccentrically mounted gear, the latter being subjected to the action of centrifugal force to'produce a braking effect on the spindle and balance in proportion to the rotary speed of the projectile. I

3. In a clock work operated mechanical fuse for artillery projectiles, a regulating device including a balance spindle, a balance carried thereby, a collet mounted on the balance spindle, a'split ring adjustable to position, a balancespring having one end thereof secured in the said collet and the other end in'the said split ring, a second 'splitring associated with the first split ring and adjustable to position relatively there-' to,.1nea1n's associated with the second split ring for controlling the oscillations o-f the outermostconvolution of the said balance spring, and ineans for maintaining thesplit rings in their relative positions.

4. In a clockwork operated mechanical fuse for artillery projectiles, a regulating device including a balance spindle, a balance carried thereby, a balance spring, a collet fixed on the balance spindle, a split ring, one end of the balance spring being secured in the collet and the other end in the split ring, the said split ring having a flange, a second split ring adjustable to position on the flange of the first split ring and having a projection within which the outermost convolution of the said balance spring passes, and means for securing the split rings in their relatively adjusted positions.

5. In a clock work operated mechanical fuse for artillery projectiles, a frame, a regulating device including a balance spindle, a balance carried thereby, a balance spring, a collet fixed on the balance spindle, a split ring, one end of the balance spring being ment with a key admitted through an opening in the frame to revolubly adjust the said second split ring to position, and means for securing the said split rings in their adjusted positions relatively to each other.

6. In a clock work operated mechanical fuse for artillery projectiles, a regulating device including a balance spindle, a balance carried thereby, a dead beat escapement, a collet mounted on the balance spindle, a split ring adjustable to position, a balance spring having one end thereof secured in the said collet and the other end in the said split ring, a second split ring associated with the first split ring and adjustable to position relatively thereto, means associated ANDRE VARAUD. 

